When rock crawling with RC its really useful to be able to use all RC functions with just one hand; especially when going on longer trail runs.
This print fixes to the FTX standard controller and allows you to steer the car using your middle finger whilst your index finger controls the throttle. There is an indent in the centre of the steering arm for your finger although it works just as well pushing the arm from either side. In practice, I have not found any issues with the steering arm being attached and steering using my other hand; in fact I think it helps with accuracy.
The steering extension is clamped around the control wheel using a M4 hex bolt (15mm), two washers and a nut. Pretty straight forward.
The files have been tweaked and improved from the printed version featured in the photo to ensure a perfect fit and to allow more access to tightened the M4 nut.
I'm currently working on a modified version for the FlySky GT3. Should be uploaded soon.